This invention relates to positioning systems and, more particularly, to an improved single cycle positioning system which utilizes an induction motor to accurately position a cyclicly movable member at a precise location within its movement cycle.
There are numerous machines where a member is cyclicly driven and it is required to stop the member at a precise location within its positional cycle. One such type of machine is a crimping press which is utilized repetitively to attach electrical terminals to the ends of wires. U.S. Pat. No. 3,343,398 discloses one such machine wherein a ram is coupled to a shaft and, during each single revolution of the shaft, the ram is moved downwardly and then back to its initial position thereby to move a crimping die on the end of the ram into engagement with a terminal. The shaft is coupled through a single revolution clutch to a flywheel which is continuously driven by a continuously operated motor. When it is desired to crimp a terminal onto a wire, the single revolution clutch is engaged to drive the shaft through a single revolution so that the ram is moved through its cycle.
While the aforedescribed arrangement is effective for its intended purpose, it suffers from a number of disadvantages. Thus, for example, the continuous running of the motor is wasteful of electrical energy and results in the generation of heat. Also, the use of a single revolution clutch causes noise and vibration. Further, the clutch has to be properly maintained and worn parts replaced.
It is therefore an object of the present invention to provide a single cycle positioning system which substitutes electronic control for a single revolution clutch.
Positioning systems utilizing servo motors are known. However, due to the type of motor required, such systems tend to be expensive. It is therefore another object of the present invention to provide a positioning system of the type described which utilizes a relatively inexpensive induction motor.